Are your apps all free?

Absolutely... it's the Android way. They contain no ads either. I will open source them as the code is cleaned up.

Why are the apps so small?

I look at this question from the other direction. Why are other apps so large? All my apps are less than 90kb, and most of that is the icons. I am very much against adding unnecessary features or excessive graphics that characterise bloatware.

Why do you say not to use Task Killers?

The Android OS operates in a different way from any other operating system you've probably seen. The emphasis is on saving power and memory, so the OS has free reign to terminate background processes it feels are no longer being used. Many programmers aren't used to this, find it scary and either cheat to force their app into memory (which hogs resources) or don't cater for it at all (which leads to app instability). Once you understand the rationale, it makes a lot of sense, and actually leads to more stable applications with better modularity and loose coupling (technical terms for better written software). Read this for more information.